What event would confirm that we have implemented an AGI system?
It is a difficult question to answer, as &mdash; for a start &mdash; we still don't really know what 'intelligence' means. It's a bit like Supreme Court Justice Potter Stewart declining to define 'pornography', instead stating that [...]I know it when I see it. AGI will be the same.

There is no single event (almost by definition), as that's not general. OK, we've got machines that can beat the best human players at chess and go, two games that were for centuries seen as an indication of intelligence. But can they order a takeaway pizza? Do they even understand what they are doing? Or, even more fundamental, know what they means in the previous sentence?

In order for a machine to show a non-trivial level of intelligent behaviour, I would expect it to interact with its environment (which is more social intelligence, an aspect that seems to be rather overlooked in much of AI). I would expect it to be aware of what it's doing/saying. If I have a conversation with a chatbot that really understands what it's saying (and can explain why it came to certain conclusions), that would be an indication that we're getting closer to AGI. So Turing wasn't that far off, though nowadays it's more achieved with smoke and mirrors rather than 'real' intelligence.

Understanding a story: being able to finish a partial story in a sensible way, inferring and extrapolating the motives of characters, being able to say why a character acted in a particular way. That for me would be a better sign of AGI than beating someone at chess or solving complex equations. Jokes that are funny; breaking rules in story-telling in a sensible way.

Writing stories: NaNoGenMo is a great idea, and throws up lots of really creative stuff, but how many of the resulting novels would you want to read instead of human-authored books? Once that process has generated a best-seller (based on the quality of the story), then we might be getting closer to AGI.

Composing music: of course you can already generate decent music using ML algorithms. Similar to stories, the hard bit is the intention behind choices. If choices are random (or based on learnt probabilities), that is purely imitation. An AGI should be able to do more than that. Give it a libretto and ask it to compose an opera around it. Do this 100 times, and when more than 70-80 of the resulting operas are actually decent pieces of music that one would want to listen to, then great.

Self-driving cars? That's not really any more intelligent (but a lot sexier!) than to walk around in a crowd without bumping into people and not getting run over by a bus. In my view it's much more a sign of intelligence if you can translate literature into a foreign language and the people reading it actually end up enjoying it (instead of wondering who translated that garbage).

One aspect we need to be aware of is anthropomorphising. Weizenbaum's ELIZA was taken for more than it was, because its users tried to make sense of the conversations they had and built up a mental model of Eliza, which clearly wasn't there on the other side of the screen. I would want to see some real evidence of intentionality of what an AGI was doing, rather than ascribing intelligence to it because it acts in a way that I'm able to interpret.